The proposal will determine and evaluate the acute effects of alcohol on both the near triad, a complex neurological system found in the visual pathway, and the tracking performance of the foot-eye system. Experiments will be performed during both the absorption and elimination phase of alcohol and over extensive blood alcohol levels (BAL) from 0-15%. Utilizing a triple function ocular monitor, accommodation, pupil size and accommodative convergence (the near triad) will be measured simultaneously for both step-changes and sinusoidal variations of the target position. Separate experiments will be performed on each of these three systems. Pursuit tracking by the foot will consist of following a mixed sinusoid input to avoid prediction and single sinusoids to study prediction. The acute effects of alcohol on these neurological elements will be evaluated utilizing Laplace Transform theory to derive best fit transfer functions before and following alcohol ingestion. Changes in the overall transfer function and its specific coefficients will be utilized as a measure of alcohol impairment. Tracking performance will be investigated in a like manner to determine if predictability is impaired or whether "learning" takes place. The development of these two systems will lead to the development of a system capable of assessing neurological impairment for chronic alcohol ingestion as well as the evaluation of the effects of substance pairs.